CHemistry chapter 2 2
Terms
undefined, object
copy deck
 scientific method
 a logical approac to solving problemsby observing and collectiong data, formulating and testing hypothesis, and formulating theories that are supported by data.
 observing
 the use of senses to obtain information it involves measurements and collecting data.
 Qualative vs. quantitative information
 Qualative is descriptive and quantitative is numerical
 a system is a
 a apecific protion of matter ina given region of space that has been selected for study during an experiment.
 hypothesis
 a testable statement
 model
 used to represent ideas which cannot be easily viewed
 theory
 broad generalizations used to explain observations.
 quantity
 something that has magnitude, size or amount
 SI system
 the system internationale which includes 7 base units, also known as the metric system
 measurement standard

an object or natureal ohenomena that is of constant balue, easy to preserve and reproduce, and pratical in size
a means of comparison 
length
mass
time
temperature
amount of substance
electric current
luminous intensity
energy 
meter
kilogram
second
kelvin
mole
ampere
candela
jule  Celsius to Kelvin
 degree C + 273 =K
 king henry died (monday)(laughing) (greedy) drinking chocolate milk

kmhmdammdmcmmm
klhldalldlclml
kghgdaggdgcgmg  dimensional analysis or factor label method
 method of solving problems based on cancellation of units
 formula for density

D=m/v
density equals mass divided by volume  how do you find the volume of irregularly shaped objects
 water displacement
 volume of cylinders
 V= pi(r)2(h)
 what is accuracy
 closeness to the read value
 what is precision
 repeatability of a measurement, how many times you come close.
 percent error is calculated by
 value (accepted) value(experimental)/ value(accepted) x 100.
 significant figures are
 valid figures actually obtained form a measurement.
 what are the rules for determining the number of significant figures.

 all nonzero digits are significant
leading zeros are not significant
captive zeros are significant
trailing zeros may or may not be significant  exact and perfect numbers
 measurements or counting and are infinite number of solutions.
 what is a graph
 a picture of data
 rules for making a good graph are

you label each axis with a unit and a description
divide each axis evenly
plot and circle data points
draw a best fit line between data points  how do you find the slope
 rise over run
 direct and indirect proportions

direct when one goes up the other quantity goes up too
indirect when one goes up the other goes down.(hyperbola)  conversion factor
 a ratio derived from the equality between two different units that can be used to convert from one unit to the other.